Apparatus for inspecting the exterior finish of containers and associated method

Abstract

Apparatus and method are provided for inspecting finish dimensions of and detecting finish defects on containers moving sequentially in a predetermined path. More than one container can be inspected simultaneously. The apparatus includes one or more inspection gauges suspended above the container path. A transport system is provided for aiding in moving containers through the gauges and simultaneously axially rotating the containers about a vertical axis. Rotation of the containers allows the inspection gauges to inspect the entire circumference of the containers at one or more levels on the container simultaneously. Defective containers are detected when the relative separation distance between the gauge plates of the inspection gauge falls outside predetermined limits. If a defective container is detected, a rejection assembly may be activated to physically remove the defective container from the container path. A suspension system permits transverse movement of the inspection gauges to accommodate non-concentric containers therethrough. The method of this invention includes inspecting containers using in the apparatus of this invention.

What is claimed is: 
     
       1. A method of inspecting exterior finish of containers moving sequentially in a predetermined path, comprising the steps of: providing an apparatus for inspecting exterior finish of containers, said apparatus having at least one inspection gauge having a pair of elongated, opposed gauge plates mounted for pivotal movement relative to one another about first pivot points on upper ends thereof, said gauge plates having gauging means thereon for engaging said container at at least one pair of generally diametrically opposed locations thereon, each said pair of locations being at a level on said container different from other said pairs of locations, sensor means operative responsive to relative pivotal movement of said gauge plates for detecting defective containers, said sensor means detecting defective containers when relative separation distance of said gauge plates where said gauge plates engage said containers caused by said container passing therebetween falls outside of predetermined limits, return spring means for urging said gauge plates in a closed position, and dampening means for reducing rebound movement of said gauge plates upon closure thereof;   moving said containers sequentially and generally continuously through said apparatus;   rotating said container about its vertical axis as it passes through said inspection gauge, whereby said gauge plates contact said container over at least its entire circumference at each said pair of locations engaged by said gauge plates;   pivoting said inspection gauge about at least one second pivot point located at or above said first pivot point to allow non-concentric containers to pass therethrough; and   stopping said rotation of said container after it passes through said gauge plates.   
     
     
       2. The method of claim 1, further including: moving said containers sequentially through said apparatus so that only one container at a time is within each inspection gauge such that more than one container is simultaneously inspected at more than one level on each said container.   
     
     
       3. The method of claim 2, further including: simultaneously inspecting a circumferential portion of said container at more than one vertically spaced level thereon.   
     
     
       4. The method of claim 3, further including: inspecting at least one vertically spaced circumferential portion of a neck region of said container, said neck region having external threads on a portion thereof.   
     
     
       5. The method of claim 4, further including: inspecting a circumferential portion of said external threads.   
     
     
       6. The method of claim 5, further including: generating an electrical signal to activate reject means when said sensor means detects a defective container.   
     
     
       7. Apparatus for inspecting exterior finish of containers moving in a predetermined path, said apparatus comprising: at least one inspection gauge disposed above the path, each said inspection gauge having a pair of elongated, opposed gauge plates mounted for pivotal movement relative to one another at first pivot points on upper ends thereof, said gauge plates having gauging means thereon for engaging containers passing therebetween at at least one pair of generally diametrically opposed locations on said container, with each said pair of locations being disposed at a level on said containers separate from other said pairs of locations, sensor means operative responsive to relative pivotal movement of said gauge plates for detecting defective containers, said sensor means detecting a defective container when relative separation distance between said gauge plates where said gauge plates contact said container caused by said container passing therebetween falls outside predetermined limits, return spring means for urging said gauge plates into a closed position, stop means for maintaining a predetermined relative separation distance between said gauge plates when in said closed position, and dampening means for reducing rebound movement of said gauge plates upon closure thereof, said dampening means includes a magnetic damper on said stop means;   said gauge plates having a total length along the path such that each container passing therebetween is inspected about its entire circumference at each level where said container is engaged by said gauge plates;   said sensor means having at least one adjustable microswitch on said stop means which is activated when separation distance of said gauge plates falls outside said predetermined limits;   transport means for moving said containers sequentially through each said gauge and axially rotating each said container about its vertical axis, said transport means including a pair of endless drive belts disposed generally longitudinally adjacent to said inspection gauges and positioned to engage opposite sides of said containers travelling through said inspection gauges, one said drive belt travelling faster than another said drive belt, whereby each container engaged by said drive belts will be propelled longitudinally along said drive belts and simultaneously be rotated about its vertical axis, said transport means further includes a container stabilizer wheel having a soft tire thereon rotatably mounted so as to engage said containers upon disengagement from said drive belts, whereby rotational movement of said containers is stopped; and   each said inspection gauge being suspended above the path by a suspension system which permits each said gauge plate to pivot in a transverse direction about at least one second pivot point at or above said first pivot point to receive non-concentric containers therethrough, said suspension system includes at least one suspension bar having one end thereof pivotally connected to an inspection gauge and having another end thereof pivotally connected to a frame for supporting said gauges, whereby transverse pivotal movement of said gauges may be achieved.   
     
     
       8. The apparatus of claim 7, further comprising means for selectively opening and closing each said inspection gauges; and   means for selectively moving said transport means into and out of position, whereby container inspection may be selectively stopped and started without disrupting said moving containers.   
     
     
       9. The apparatus of claim 7, wherein each said containers has a neck region having external threads on a portion thereof; and   said gauge plates have means thereon for engaging said neck region at least one vertically spaced pair of generally diametrically opposed locations.   
     
     
       10. The apparatus of claim 9, further comprising reject means in communication with said sensor means for identifying defective containers detected by said sensor means.   
     
     
       11. The apparatus of claim 10, wherein said reject means includes a rejection assembly for physically removing defective containers from the path.   
     
     
       12. The apparatus of claim 11, wherein said reject means further includes signal generating means electrically connected to said rejection assembly and in communication with said sensor means for generating an electrical signal which activates said rejection assembly when a defective container is detected.   
     
     
       13. The apparatus of claim 12, wherein activation of said microswitch activates said reject means.   
     
     
       14. The apparatus of claim 9, wherein said gauge plates have gauging means thereon for engaging each said container passing therebetween at more than one vertically spaced pair of generally diametrically opposed locations, whereby the diameter of said container can be measured and surface irregularities on said container may be inspected for about substantially the entire circumference of said container at each level of each said pair of locations.   
     
     
       15. The apparatus of claim 14, wherein at least one said pair of vertically spaced locations is on said external threads.   
     
     
       16. The apparatus of claim 13, wherein four said inspection gauges relatively spaced longitudinally along said path are provided with the total length of said gauge plates of all said inspection gauges being substantially equal to about 2 to 4 times the circumference of each said container at the levels being inspected and the length of each said gauge plate of each said inspection gauge is shorter than the smallest diameter of said container at the level being inspected, whereby more than one container can be simultaneously inspected about their entire circumferences-at the levels of each said pair of locations.   
     
     
       17. The apparatus of claim 16, wherein said gauges are spaced apart along the path by a distance sufficient to accommodate said suspension system.   
     
     
       18. The apparatus of claim 17, wherein said path extends generally longitudinally along a production line.